2007 LR3 4.4, has about 188K. I've been getting intermittent P0175 codes. I had this last year, replaced the MAF, was good for awhile. Then as the weather changed from hot to cold, the code popped up again. not running rough, local shop didn't see anything, erased the code and it was fine for about a month, then it's been on and off since March. It'll be fine for a few days to a few weeks, code pops up, reset, then it's fine for a month, pops up, put in a full tank of gas, goes away on it's own (has only done this once). I got a new MAF a few weeks ago, and it's been fine, weather got a little cooler and the code popped up again. I'm at a loss for what to even check anymore. I put in new upstream O2 sensors (maintenance) and seems the bank one is bad, getting a P0133 now and the P0175 is still there. I don't have a gap just a cheap code reader for basics. The injectors, spark plugs, and coils were replaced last year, only 7-8K on them. Air filter was replace last month when this popped up again as the same time as the MAF.

 

P0175 is for bank 2, P0133 is bank one indicating your rich issue is one one side and your apparent fault O2 is on the other. What brand MAF sensors? What brand O2 sensors? Did you verify the gap of the plugs before installing? 1mm is spec, which is 0.04". What brand were the injectors and were they new or rebuilds? My guess is you have a bad injector that sticks from time to time causing the rich condition.

 

So O2, I think the plug was loose, i checked it again, put on another 40 miles and no issues, some highway, some stop and go. P0175 is back.
OEM - MAF
Rebuilt denso injectors
After taking a minute to not be frustrated, i think you're right it's an injector issue, I remember running cleaner through them after install based on how it was running. Cleared it up for awhile, but the code eventually came back even though it was running well.

 

@DakotaTravler You have a recommendation on fuel injectors? so far all your recs have worked out well from the white label to the OEM. Thanks again!

 

Well in theory the Denso rebuilds should be fine. No misfire codes? Because right now you can only know what side of the engine there may be a bad injector, not the exact one. You might be able to cold start the engine and run it for a short while then pull all the spark plugs on that bank and see if one looks super wet. Or by now you may even be able to tell just by looking to see if one has excess carbon compared to the others. The idea is just to locate and replace the one bad injector. If you have your old ones, you could even toss an old one in.

I myself rebuilt my injectors but I do have a complete set of Denso rebuilds from CarQuest ready to go in when I fell like it. I plan to get them flow tested at a shop first to make sure none are bad.

 

I guess I'll try that, I have the old ones so guess we'll try rebuilding those, thanks again

 

Were there issues with the old? I am just wondering if you had issues because maybe you have issues again due to fuel contamination or such? The filters should catch most tho.

 

Ok, took longer than I thought. I got new upstream oxygen sensors switched them out and the new one on bank1 turned out to be bad(started getting o2 errors), so put the old one back in while I waited for the replacement, but that took care of the p0175. Got the replacement and bank1 error is gone. New downstreams should be here today. also got the rebuild kit for the injectors but i'll just leave as is and see how this works for now.

thanks again for the assist.